add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/arch/arm/kernel/vdso.c
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@@ -1,20 +1,9 @@
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+// SPDX-License-Identifier: GPL-2.0-only
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 /*
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  * Adapted from arm64 version.
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  *
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  * Copyright (C) 2012 ARM Limited
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  * Copyright (C) 2015 Mentor Graphics Corporation.
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- *
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- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License version 2 as
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- * published by the Free Software Foundation.
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- *
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- * This program is distributed in the hope that it will be useful,
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- * but WITHOUT ANY WARRANTY; without even the implied warranty of
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- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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- * GNU General Public License for more details.
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- *
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- * You should have received a copy of the GNU General Public License
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- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
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  */
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 #include <linux/cache.h>
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@@ -34,6 +23,8 @@
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 #include <asm/vdso.h>
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 #include <asm/vdso_datapage.h>
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 #include <clocksource/arm_arch_timer.h>
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+#include <vdso/helpers.h>
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+#include <vdso/vsyscall.h>
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 #define MAX_SYMNAME	64
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@@ -48,7 +39,7 @@
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  * The VDSO data page.
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  */
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 static union vdso_data_store vdso_data_store __page_aligned_data;
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-static struct vdso_data *vdso_data = &vdso_data_store.data;
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+struct vdso_data *vdso_data = vdso_data_store.data;
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 static struct page *vdso_data_page __ro_after_init;
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 static const struct vm_special_mapping vdso_data_mapping = {
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@@ -88,7 +79,7 @@
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 /* Cached result of boot-time check for whether the arch timer exists,
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  * and if so, whether the virtual counter is useable.
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  */
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-static bool cntvct_ok __ro_after_init;
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+bool cntvct_ok __ro_after_init;
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 static bool __init cntvct_functional(void)
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 {
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@@ -193,6 +184,7 @@
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 	if (!cntvct_ok) {
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 		vdso_nullpatch_one(&einfo, "__vdso_gettimeofday");
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 		vdso_nullpatch_one(&einfo, "__vdso_clock_gettime");
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+		vdso_nullpatch_one(&einfo, "__vdso_clock_gettime64");
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 	}
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 }
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@@ -249,7 +241,7 @@
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 	return PTR_ERR_OR_ZERO(vma);
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 }
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-/* assumes mmap_sem is write-locked */
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+/* assumes mmap_lock is write-locked */
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 void arm_install_vdso(struct mm_struct *mm, unsigned long addr)
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 {
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 	struct vm_area_struct *vma;
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@@ -275,84 +267,3 @@
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 		mm->context.vdso = addr;
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 }
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-static void vdso_write_begin(struct vdso_data *vdata)
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-{
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-	++vdso_data->seq_count;
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-	smp_wmb(); /* Pairs with smp_rmb in vdso_read_retry */
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-}
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-
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-static void vdso_write_end(struct vdso_data *vdata)
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-{
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-	smp_wmb(); /* Pairs with smp_rmb in vdso_read_begin */
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-	++vdso_data->seq_count;
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-}
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-
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-static bool tk_is_cntvct(const struct timekeeper *tk)
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-{
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-	if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER))
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-		return false;
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-
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-	if (!tk->tkr_mono.clock->archdata.vdso_direct)
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-		return false;
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-
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-	return true;
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-}
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-
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-/**
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- * update_vsyscall - update the vdso data page
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- *
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- * Increment the sequence counter, making it odd, indicating to
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- * userspace that an update is in progress.  Update the fields used
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- * for coarse clocks and, if the architected system timer is in use,
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- * the fields used for high precision clocks.  Increment the sequence
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- * counter again, making it even, indicating to userspace that the
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- * update is finished.
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- *
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- * Userspace is expected to sample seq_count before reading any other
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- * fields from the data page.  If seq_count is odd, userspace is
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- * expected to wait until it becomes even.  After copying data from
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- * the page, userspace must sample seq_count again; if it has changed
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- * from its previous value, userspace must retry the whole sequence.
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- *
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- * Calls to update_vsyscall are serialized by the timekeeping core.
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- */
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-void update_vsyscall(struct timekeeper *tk)
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-{
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-	struct timespec64 *wtm = &tk->wall_to_monotonic;
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-
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-	if (!cntvct_ok) {
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-		/* The entry points have been zeroed, so there is no
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-		 * point in updating the data page.
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-		 */
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-		return;
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-	}
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-
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-	vdso_write_begin(vdso_data);
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-
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-	vdso_data->tk_is_cntvct			= tk_is_cntvct(tk);
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-	vdso_data->xtime_coarse_sec		= tk->xtime_sec;
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-	vdso_data->xtime_coarse_nsec		= (u32)(tk->tkr_mono.xtime_nsec >>
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-							tk->tkr_mono.shift);
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-	vdso_data->wtm_clock_sec		= wtm->tv_sec;
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-	vdso_data->wtm_clock_nsec		= wtm->tv_nsec;
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-
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-	if (vdso_data->tk_is_cntvct) {
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-		vdso_data->cs_cycle_last	= tk->tkr_mono.cycle_last;
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-		vdso_data->xtime_clock_sec	= tk->xtime_sec;
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-		vdso_data->xtime_clock_snsec	= tk->tkr_mono.xtime_nsec;
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-		vdso_data->cs_mult		= tk->tkr_mono.mult;
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-		vdso_data->cs_shift		= tk->tkr_mono.shift;
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-		vdso_data->cs_mask		= tk->tkr_mono.mask;
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-	}
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-
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-	vdso_write_end(vdso_data);
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-
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-	flush_dcache_page(virt_to_page(vdso_data));
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-}
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-
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-void update_vsyscall_tz(void)
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-{
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-	vdso_data->tz_minuteswest	= sys_tz.tz_minuteswest;
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-	vdso_data->tz_dsttime		= sys_tz.tz_dsttime;
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-	flush_dcache_page(virt_to_page(vdso_data));
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-}